Terms were not disclosed.
This is Content Partners' largest buyout to date and expands on its catalogue of entertainment properties, which includes interests in 119 movies and five TV series.
Content Partners LLC said Thursday that the deal makes it an equal stakeholder with CBS Corp., which owns the other 50 per cent interest.
Content Partners and CBS will each own half the rights of the franchise, which include the television series "CSI," ''CSI: New York" and "CSI Miami." CBS will control all domestic and international distribution rights to the series.
Bank of America Merrill Lynch and J.P. Morgan provided financing for the transaction.